Questions regarding split-control
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I found two different sources online regarding this topic: under normal conditions, 1) the air pressure ranges for the two stages in split-control systems are generally set at 0.02~0.06 MPa and 0.06~0.10 MPa respectively. One of these statements is correct and the other is incorrect – please help identify which one! 2. In a split-range control system, the range for the split range four is generally set as two pressure segments: 0.02–0.06 MPa and 0.06–0.10 MPa. (×) I don’t understand what this question means; please help me out! Thank you!
It should be: in a split-range control system, the range for each split segment is generally divided into four pressure levels of 0.02–0.04 MPa, 0.04–0.06 MPa, 0.06–0.08 MPa, and 0.08–0.10 MPa.
It doesn’t seem like this term is used from a DCS perspective either, right?
It’s usually divided this way; I don’t see any problem with it.
I would like to ask about this segmented control you mentioned – are you using base-type regulators? It seems different from what I’ve seen
Could you send a picture so I can see what it looks like? I’m using a CS3000 system; generally, just setting up proportional control in the control system is sufficient – I haven’t heard of any need to adjust pressure
Split-range control is a 4–20mA signal sent to two or more control valves; the most common case is sending it to two control valves. There are two approaches to split-range control: 1. For the 4–20mA output signal, after determining the division points (for example, if it is 12mA, then valve A uses 4–12mA while valve B uses 12–20mA), adjust the zero point and range of the electrical valve positioners on both valves ； 2. When using DCS, after determining the division point, the output from the controller module is adjusted through calculation and sent to the two AO channels, with each AO channel delivering a signal of 4–20 mA.
Disk meters are completed by making adjustments on the meter itself.
The CS3000 system enables proportional control; all system outputs are 4-20MA, and the wind pressure at the site remains constant. In contrast, the output current of traditional systems is segmented, and the wind pressure at the site is also segmented; the ranges for these segments are generally 0.02–0.04, 0.04–0.06, 0.06–0.08, and 0.08–0.10 MPa. Both can be achieved, but the current systems and actuators are more convenient as no additional setup is required.
Currently, the stage control of control systems is determined based on the requirements of the process, and it is generally specified by the process or the design. It also depends on whether there are two stages, three stages, or more stages; as for the stage curve between 0% and 100%, it is determined based on the process design, with some being linear and others nonlinear. So it can’t be generalized. Regarding the question posted by the original poster, I wonder if it relates to the regulators used in the old bases or something like that? For using DCS or PLCs nowadays, the significance of this problem is minimal. If we have to determine right from wrong, I think it’s wrong, at least it’s not precise in expression, because whether it should be divided equally depends on the process design.